Glutamine-enriched parenteral nutrition after autologous peripheral blood stem cell transplantation: effects on immune reconstitution and mucositis

BACKGROUND AND OBJECTIVES: Glutamine (gln), a non-essential amino acid, has recently received increasing attention because it becomes essential during stress and catabolic states: glutamine seems to modulate immune function and to promote faster intestinal healing after chemotherapy. We designed two consecutive randomized clinical trials to evaluate the role of glutamine-enriched parenteral nutrition (GEPN) in patients with hematologic malignancies submitted to high dose chemotherapy and autologous peripheral blood stem cell transplantation (aPBSCT) or immunoselected CD34+ aPBSCT. DESIGN AND METHODS: In study1, the Gln group (12 patients) received total parenteral nutrition (TPN) enriched with glutamine 20 g from day +1 after aPBSCT, while the placebo group (15 patients) received TPN lacking in glutamine (placebo). In study2, the Gln group (10 patients) received TPN enriched with glutamine 13.46 g from day +1, while the placebo group (11 patients) received a placebo. RESULTS: In the first study, a lymphocyte count >0.5 109/L was achieved on day 16.5 in the Gln group and on day 29 in the placebo group (p=0.005); in the second study, the lymphocyte count >0.5 109/L was achieved on day 18 in the Gln group and on day 29 in the placebo group (p=0.009). Lymphocyte subset analysis showed an increase of CD3+ and CD4+ and normalization of the CD16+CD56+ subset. Furthermore patients receiving GEPN showed a decrease in the mucositis severity peak calculated by the DMS (daily mucositis score: sum of the daily score of signs and symptoms) (p=0.047). INTERPRETATION AND CONCLUSIONS: GEPN is safe and effective and improves lymphocyte recovery after aPBSCT; further studies are needed to assess the clinical benefits of such an approach in order to justify its economic impact